CONFIDENTIAL! 

FOR  OFFICIAL  USE  ONLY 


NOTES 


ON 


LIAISON  IN 
MODERN  WARFARE 

COMPILED  FROM  THE  LATEST  SOURCES 


APRIL,  1917 


ARMY  WAR  COLLEGE 


WASHINGTON 

GOVERNMENT  PRINTING  OFFICE 
1917 


WAR  DEPARTMENT. 

Document  No.  579. 

OFFICE  OF  THE  ADJUTANT  GENERAL. 


WAR  DEPARTMENT, 

WASHINGTON,  April  30,  1917. 

The  following  notes  on  Liaison  in  Modern  Warfare  are  published 
for  the  information  and  guidancg  of  all  concerned. 
[2588951,  A.  G.  0.] 

BY   ORDER   OF  THE    SECRETARY   OF  WAR: 

H.  L.  SCOTT, 
Major  General,  Chief  of  Staff. 
OFFICIAL: 

H.  P.  McCAIN, 

The  Adjutant  General. 

(3) 


NOTES  ON  LIAISON. 


1.  The  question  of  "Liaison"  in  battle  is  of  the  utmost  impor- 
tance, as  in  modern  warfare  the  complete  coordination  of  the  differ- 
ent arms,  and  of  the  different  units  in  the  line,  is  absolutely  neces- 
sary for  success. 

2.  In  the  armies  of  Europe  the  question  has  received  the  most 
serious  attention,  and  the  service  of  "Liaison"  has  been  organized 
with  a  view  to  obtaining  the  most  complete  coordination  possible, 
from  the  general  headquarters  down  to  the  smallest  units  in  the 
firing  line. 

3.  Military  attaches  are  assigned  to  the  general  headquarters  in 
France,  as  "Officiers  de  liaison,"  from  each  of  the  Allied  Powers. 

Several  staff  officers  are  detailed  from  the  general  headquarters 
as  "  Officiers  de  liaison"  and  are  assigned  to  the  several  armies;  these 
officers  travel  at  night  from  headquarters  to  the  army  to  which  they 
are  assigned,  remain  with  the  army  through  the  day,  and  return  the 
following  night  to  headquarters.  Similarly,  liaison  officers  are  de- 
tailed from  the  several  army  headquarters  to  the  different  corps; 
from  the  corps  to  the  divisions;  and  from  the  divisions  to  the 
brigades. 

4.  For  the  smaller  units  the  detail  of  "Officiers  de  liaison  "  is  fixed 
by  regulations,  and  the  officers  are  regularly  trained  in  their  duties; 
thus,  in  an  Infantry  regiment,  the  regiment  furnishes  a  mounted 
officer  for  brigade  headquarters;  each  battalion  sends  an  officer  or  a 
noncommissioned  officer  and  a  cyclist  to  the  colonel;  and  each  com- 
pany sends  a  soldier  to  the  battalion  commander.     In  an  Artillery 
regiment,  an  officer  is  sent  to  the  corps  or  division  commander;  each 
battalion  sends  an  officer  to  the  regimental  commander,  and  each 
battery  sends  a  sergeant  to  the  battalion  commander.     Forward 
observation  officers  are  also  sent  to  the  Infantry  trenches  to  keep 
the  Artillery  informed  of  the  needs  of  the  Infantry. 

5.  The  principal  means  of  communication  used  are:  The  tele- 
phone, telegraph,  wireless,  aeroplanes,  mounted  messengers,  auto- 
mobiles, and  motorcycles,  and  at  the  front,  runners,  visual  signals, 
rockets,  and  carrier  pigeons. 

(5) 


6 

6.  The  main  reliance  for  the  service  of  the  lines  of  information  is 
the  telephone.     In  the  German  Army  it  is  the  sole  instrument  em- 
ployed within  the  sphere  of  the  army  corps.     The  telegraph  is  used 
only  for  connecting  up  corps  headquarters  with  the  higher  com- 
manders in  rear.    With  the  Allies,  the  telephone  is  the  principal 
means  of  communication  from  the  brigade  headquarters  down  to  the 
fighting  line. 

The  main  lines  are  buried  at  least  6  feet  under  the  ground  in  lead 
cables  until  the  trenches  are  reached :  from  here  the  lines  are  run 
along  the  communicating  trenches,  bracketed  from  the  sides  2  or  3 
feet  below  the  surface,  or  buried  below  the  floor  of  the  trenches;  in 
the  firing  trenches  the  lines  are  bracketed  along  the  firing  side  of 

the  trench. 

7.  Each  battalion  commander  is  connected  by  telephone  with 
each  company  commander,  with  the  Artillery  observers,  with  the 
Artillery  commander,  and  with  bis  colonel;  also  with  adjacent 
battalions  on  either  side. 

8.  When  a  bombardment  commences  the  lines  are  being  continu- 
ally cut,  and  it  has  been  foiind  necessary  to  run  a  number  of  lines 
for  each  line  of  communication,  and  even  then  telephone  communi- 
cation is  often  completely  interrupted,  and  the  only  communication 
is  by  visual  signals  or  messengers.     In  case  of  an  advance  the  prob- 
lem becomes  almost  hopeless.     The  telephone  linemen  follow  the 
first  line  of  the  attack,  but  they  can  not  travel  as  fast  as  the  line,  and 
they  are  obliged  to  do  their  work  on  a  terrain  which  is  beaten  by 
Artillery  fire;  few  men  will  arrive  safely  at  the  point  previously 
assigned  them  for  establishing  their  station. 

9.  Both  the  Germans  and  the  Allies  are  using  '•  listening  appar- 
atus" for  the  purpose  of  overhearing  the  enemy's  telephone  com- 
munications, by  means  of  grounded  wires  and  induction,  and  at  the 
present  time  the  lines  in  the  forward  trenches  are  being  put  in  with 
metallic  circuit  (without  ground),  and  the  strictest  regulations  are 
being  enforced  as  to  the  use  of  the  telephones;  no  private  messages 
are  allowed,  and  all  messages  are  in  code.    Even  conversation  about 
any  movement  or  plan  is  forbidden  in  the  forward  trenches. 

10.  Wireless  has  found  relatively  little  use,  it  being  slow,  liable  to 
interruptions,  and  the  predominance  of  position  warfare  rendering 
it  more  or  less  superflous.     It  is  principally  used  in  connecting  the 
commander  of  the  army  with  distant  elements  with  whom  telephone 
connection  could  hardly  be  established.     It  is  also  used  to  a  certain 
extent  from  aeroplanes  in  regulating  artillery  fire,  especially  the 
heaw  batteries. 


11.  Automobiles  and  motorcycles  are  of  the  greatest  importance 
to  the  different  headquarters  in  maintaining  easy  and  rapid  com- 
munication between  armies,  corps,  divisions,  and  even  brigades; 
but  as  the  fighting  line  is  approached,  they  are  no  longer  practicable, 
as  the  roads  are  swept  by  shells  from  the  hostile  artillery. 

12.  Aeroplanes  are  used  in  different  ways  in  the  service  of  in- 
formation : 

Contact  aeroplanes  are  assigned  for  service  with  the  infantry  in  an 
attack.  During  the  attack  they  can  fly  low  with  comparative  safety 
and  can  discover  the  movements  of  the  enemy,  locate  his  reserves, 
machine-gun  emplacements,  etc.,  and  give  prompt  notice  to  the 
infantry.  Contact  aeroplanes  communicate  with  the  infantry  by 
means  of  a  Klaxon  horn,  Very's  signals,  or  by  dropping  messages  in 
tubes  from  overhead.  The  wireless  is  only  used  by  contact  aero- 
planes for  signaling  to  the  artillery. 

Other  aeroplanes  are  assigned,  for  service  with  the  artillery,  and 
signal  with  wireless  only,  using  a  prearranged  code.  The  clock 
system  is  used,  the  target  being  considered  always  at  the  center  of 
the  dial  with  true  north  at  12  o'clock;  concentric  circles  represent 
50,  100,  200,  300,  400  yards  from  the  target,  and  are  marked  by  the 
letters  A,  B,  C,  D,  etc.,  while  the  dial  is  marked  by  numbers  from 
1  to  12.  Thus  a  signal  ''4  B"  would  mean  that  the  shot  fell  100 
yards  from  the  target  at  4  o'clock. 

13.  Recent  instructions  to  the  British  Armies  include  very  com- 
plete instructions  for  keeping  up  communications  during  and  imme- 
diately after  an  assault.    These  instructions  have  been  evolved 
from  over  two  years  of  experience  in  actual  warfare,  and  probably 
can  not  be  improved  on  at  the  present  time. 

BRITISH  INSTRUCTIONS. 

"SIGNAL  COMMUNICATIONS." 

1.  The  rapid  establishment  of  good  signal  communications, 
immediately  after  the  assault,  is  one  of  the  most  important,  though 
one  of  the  most  difficult,  things  to  deal  with.  No  possible  means 
of  keeping  up  communications  must  be  neglected. 

Particular  attention  to  the  subject  during  training  and  careful 
preparation  before  the  assault  are  the  best  means  of  assuring  success. 

Considerations  of  topography  and  the  siting  of  our  own  and  the 
hostile  trenches  will  decide  the  methods  which  give  most  promise 
of  success,  and  on  these  methods  every  effort  should  be  concentrated. 


8 

The  parties  required  for  establishing  each  system  must  be  definitely 
told  off  and  properly  organized  beforehand,  and  should  be  trained 
to  their  particular  duties  at  all  rehearsals. 

2.  Cable  lines  for  telephones  and  tekgraph*. — (/)  This  is  the  inn.st 
valuable  form  of  communication,  and  every  effort  must  be  made 
to  establish  the  lines  securely  at  the  earliest  possible  moment. 
To  render  cable  lines  reasonably  secure  requires  time  and  labor, 
and  can  only  be  effected  by  burying  them  to  a  depth  of  6  feet  or 
more. 

(ii)  The  extent  to  which  hastily  laid  lines  on  the  surface  can  be 
kept  through  depends  on  the  amount  of  hostile  shelling. 

Laddered  l  lines  are  very  useful,  and  can  be  quickly  constructed 
after  the  assault. 

The  vicinity  of  villages,  woods,  and  roads,  which  are  always 
heavily  shelled,  should  be  avoided  as  far  as  possible  when  selecting 
cable  Kmt-es. 

Communication  trenches  in  the  enemy's  lines,  which  will  not  be 
required  for  consolidation,  should  be  previously  selected  and 
alloted  as  cable  trenches;  the  cable  can  be  buried  in  these  when 
labor  is  available  in  less  time  than  would  be  required  to  dig  a  new 
cable  trench.  The  latter  is  more  likely  to  be  noticed  that  the  old 
communicating  trench,  and,  moreover,  the  ojd  trench  is  likely  to 
have  dugouts  in  it  which  can  be  used  for  test  points. 

(iii)  Cables  must  be  run  out  immediately  behind  the  last  wave 
of  the  assaulting  column,  the  linesmen  following  a  previously 
selected  route;  the  cable  should  be  carried  right  through  to  the 
trench  which  is  being  consolidated,  and  offices  established  at  points 
in  this  trench  line  which  have  been  previously  selected  after 
studying  maps  and  air  photographs. 

(u')  As  soon  as  this  has  been  done,  efforts  must  be  concentrated 
on  the  maintenance  of  one  or  two  lines  leading  to  important  points; 
it  is  a  waste  of  time  and  labor  to  attempt  to  maintain  all  the  lines. 
Existing  dugouts  in  the  enemy's  trenches  must  be  told  off  as  test 
stations  on  the  cable  route,  and  maintenance  parties  previously 
detailed  must  be  stationed  at  these  test  stations. 

(v)  Special  working  parties  must  be  placed  at  the  disposal  of 
the  commanding  officer,  division  signal  company,  for  the  purpose 
of  burying  the  cable  across  "No  man's  land,"  and  thence  forward, 
via  old  communication  trenches,  to  the  consolidated  line.  The 
parties  will  seldom  be  able  to  start  work  before  the  night  after  the 
assault. 

1  Lines  run  above  the  ground,  supported  on  poles,  trees,  etc. 


(t'l)  Where  Russian  saps1  have  been  run  out,  it  may  be  possible 
to  get  the  cable  a  part  of  the  way  across  "No  man's  land  "  before  the 
assault,  by  laying  the  cable  at  the  bottom  of  the  sap;  then  when  the 
roof  of  the  sap  is  broken  in,  the  cable  will  be  buried  sufficiently  to 
protect  it  from  shrapnel  and  also  from  traffic  in  the  sap. 

3.  Visual  signals. — (i)  Where  the  topography  of  the  ground  is 
suitable,  good  results  can  be  obtained  with  visual  signals. 

This  system  depends  more  than  any  other  on  previous  prepara- 
tion; all  details  must  be  worked  out,  points  where  it  is  proposed 
to  establish  stations  in  the  enemy's  lines  being  approximately 
located  by  reconnaissance  and  by  the  study  of  maps.  In  this  con- 
nection enemy  machine-gun  emplacements  have  been  found  valua- 
able. 

When  completed  the  scheme,  with  a  sketch  map,  must  be  issued 
to  all  concerned. 

Back  stations  in  our  own  lines  must  be  specially  prepared  and 
provided  with  overhead  cover. 

(ii)  A  selected  officer,  either  of  the  signal  service  or  an  officer  in 
charge  of  battalion  signals,  should  be  placed  in  charge  of  the  organ- 
ization, and  should  be  given  the  necessary  personnel  and  equipment 
required  to  work  the  scheme. 

(Hi)  Each  signal  station  to  be  established  in  the  enemy's  lines 
should  be  allotted  to  a  definite  battalion.  The  personnel  detailed 
for  each  station  will  assemble  at  the  battalion  headquarters  prior 
to  the  assault,  and  will  be  sent  forward  by  the  battalion  commander 
as  soon  as  the  objective  has  been  gained.  They  should  not  be  sent 
over  with  the  assaulting  columns. 

The  personnel  should  be  lightly  equipped;  they  must  carry  the 
signaling  equipment  fastened  to  the  person  in  as  inconspicuous  a 
manner  as  possible,  while  yet  leaving  them  free  to  use  their  weapons 
if  necessary. 

(iv)  The  signalers  of  assaulting  companies  move  with  the  company 
commander,  and  should  carry  signaling  shutters  for  the  purpose  of 
getting  into  communication  with  their  own  unit  as  soon  as  possible 
after  the  objective  has  been  reached  and  before  the  main  visual 
scheme  has  been  established. 

Lamps  should  be  reserved  for  the  main  scheme ;  they  are  too  bulky 
to  be  carried  in  the  assault  and  also  are  difficult  to  replace. 

(v)  All  visual  signallers  need  special  training  to  give  them  confi- 
dence iu  repeating  a  message  several  times  to  a  known  back  station 

1  Saps  run  underground. 


10 

which  may  not  be  able  to  reply  forward;  it  is  most  desirable,  how- 
ever, that  the  back  stations  should  acknowledge  whenever  possible. 

4.  Pigeons. — These  are  invaluable  when  properly  organized  and 
used.  The  pigeons  and  personnel  available  must  be  definitely 
allotted  to  the  different  units,  and  arrangements  must  be  made  for 
maintaining  the  supply  of  pigeons. 

At  the  commencement  of  the  assault  the  pigeons  and  pigeon  men 
must  be  kept  back  at  battalion  headquarters,  and  sent  forward  as 
soon  as  the  position  has  been  gained.  The  men  must  be  given  defi- 
nite orders  as  to  whom  they  are  to  report  and  must  be  provided  with 
a  guide  if  necessary. 

In  the  front  lines,  pigeons  must  be  kept  in  dugouts  to  protect  them 
from  shell  fire,  mud  and  wet,  as  much  as  possible. 

Pigeons  should  be  reserved  for  important  messages;  all  officers 
should  be  instructed  how  to  write  clear  and  concise  messages  in  the 
Pigeon  Message  Book. 

o.  Wireless. — (t)  A  wireless  set,  placed  at  the  disposal  of  a  division 
by  the  corps,  must  be  allotted  to  a  definite  commander,  or  to  a  spe- 
cially appointed  officer,  who  will  be  responsible  for  deciding  what 
messages  are  to  be  sent  by  wireless  and  for  arranging  for  the  mes- 
sages to  be  coded. 

(M)  Wireless  should  be  reserved  for  urgeut  measages,  such  as 
calls  for  barrage  fire,  etc.;  the  message  must  be  short  and  concise,  to 
facilitate  coding  and  decoding. 

(Hi)  At  the  commencement  of  an  assault  a  wireless  set  should  not, 
as  a  rule,  be  in  advance  of  brigade  headquarters;  but  as  soon  as  the 
position  has  been  gained,  a  wireless  set  should  be  sent  forward  to  a 
selected  battalion  headquarters,  or  to  a  selected  position  if  the  site 
of  the  battalion  headquarters  is  not  suitable. 

(iv)  A  commander  ordering  a  wireless  set  to  move  forward  will 
arrange  for— 

(a)  Written  orders  as  to  whom  the  party  are  to  report  to,  and 

at  whose  disposal  the  set  is  to  be  placed. 
(6)  A  carrying  party  of  six  men. 
(c)  A  guide  to  the  new  position. 

(v)  As  far  as  possible,  the  points  to  which  the  wireless  sets  are  to 
move  forward  must  be  decided  on  before  the  assault  and  notified  to 
all  commanders  concerned;  otherwise  the  latter  will  be  unaware  of 
the  existence  of  wireless  communication  in  the  forward  area,  and 
will  consequently  not  make  use  of  it. 


11 

(ri)  It  is  impossible  to  obtain  good  results  from  the  delicate  wire- 
less instruments  unless  the  set  is  installed  in  a  reasonably  dry  dugout, 
which  should  be  reserved  for  wireless  only. 

Heavily  shelled  areas  must  be  avoided,  otherwise  the  difficulty  of 
maintaining  the  aerial  may  render  the  set  useless. 

6.  Runners. — This  is  the  one  means  of  communication  which  can 
be  relied  on  when  all  other  means  fail;  and,  therefore,  commanders 
must  devote  great  care  to  the  training  and  organization  of  their 
runners.  Company  runners  must  be  trained  with  their  companies. 

Opinions  vary  as  to  the  actual  number  required ;  the  following  has 
been  found  to  be  a  good  average  number  of  men : 

At  battalion  headquarters .' 10 

At  company  headquarters 4 

Each  platoon  commander  also  requires  a  runner. 

Runners  should  be  lightly  equipped  and  should  wear  a  distinctive 
mark;  they  should  be  young,  lightly  built,  and  intelligent.  Every 
man  must  be  thoroughly  familiar  with  all  the  routes  to  all  the  prin- 
cipal centers  within  their  battalion  sector,  i.  e.,  to  all  company 
headquarters,  and  not  only  to  their  own,  to  all  forward  dumps,1  to 
the  headquarters  of  battalions  on  the  flanks,  to  the  headquarters  of 
the  brigade,  and  to  the  advanced  report  center  (station  established 
in  advance  of  headquarters,  generally,  at  end  of  buried  cable,  for 
relaying  messages) . 

It  must  be  impressed  upon  all  runners  that  the  quicker  they  go  the 
safer  they  arc. 

Company  and  platoon  runners  must  go  forward  with  their  respec- 
tive commanders.  Runners  must  be  sent  in  turn  and  must  be  rested 
as  far  as  possible  when  not  actually  at  work. 

Where  messages  have  to  be  carried  a  long  distance,  e.  g.,  to  bri- 
gades, some  arrangement  of  relays  is  required.  The  establishment 
of  a  brigade  advanced  report  center,  well  forward,  at  the  head  of 
the  buried  cable,  if  existing,  is  useful.  Battalion  runners  will 
bring  their  messages  to  this  point,  whence  the  contents  can  be 
telephoned  to  brigade  headquarters,  the  actual  messages  themselves 
being  sent  on  by  special  brigade  runners. 

Relay  posts  may  often  be  required  between  brigade  headquarters 
and  advanced  division  headquarters.  Every  relay  post  must  be 
labeled  and  numbered. 

On  no  account  should  any  verbal  message  be  sent  by  runners; 
every  message  must  be  in  writing,  and  verbal  messages  should  be 
ignored. 

Ammunition  distributing  stations. 


12 

7.  Artillery  messages. — Company   and   battalion   commanders  of 
assaulting  units  must  be  prepared  to  assist  Artillery  liaison  officers 
in  getting  their  messages  back.     The  artillery  can  not  always  provide 
sufficient  runners  for  their  forward  officers ;  and  where  it  is  not  possible 
to  keep  a  line  open  owing  to  shelling,  an  infantry  runner  will  often 
be  the  only  means  of  getting  an  artillery  message  through. 

There  must  be  the  closest  cooperation  between  the  signal  service 
of  the  division  and  the  artillery  as  regards  the  transmission  of 
artillery  messages;  and,  in  deciding  on  the  means  of  communica- 
tion to  be  established,  the  needs  of  the  artillery  must  be  considered 
and  provided  for  as  far  as  possible,  particularly  in  the  buried  cbale 
routes  forward  from  our  jumping-off 1  trenches. 

8.  Flank  liaison  officers. — -To  insure  that  neighboring  commanders 
are  kept  regularly  informed  as  to  the  progress  of  events,  liaison  offi- 
cers must  be  exchanged  by  all  assaulting  brigades  and  battalions 
with  the  correspor  ling  brigade  or  battalion  on  either  flank. 

The  duty  of  the  liaison  officer  is  to  keep  his  own  commander 
constantly  informed  of  the  progress  and  situation  of  the  unit  with 
which  he  is  in  liaison .  Every  liaison  officer  must  be  provided  by 
Ms  own  unit,  with  some  means  of  communication. 

AEROPLANES. 

Contact  patroi  work  by  aeroplane  is  designed  to  supplement,  but 
in  no  way  take  the  place  of  other  systems  of  communication. 

Observers  must  be  fully  informed  as  to  the  plan  of  attack,  the 
disposition  of  the  troops  with  whom  they  are  working,  and  their 
objectives.  Before  going  up,  the  observer  should  always,  if  possi- 
ble, visit  the  division,  or,  if  the  operation  is  a  small  one,  the 
brigade  concerned,  in  order  to  obtain  all  the  detailed  information 
possible.  He  should  synchronize  his  watch  with  the  staff,  so  that 
he  may  know  exactly  when  to  look  for  the  attack  to* commence. 

Aeroplanes  detailed  for  contact  work  must  have  special  markings, 
which  should  be  known  to  all  ranks  of  the  Infantry  with  which  they 
are  working.  They  will,  in  addition,  carry  a  Klaxon  horn  and 
Very's  lights  for  the  purpose  of  making  themselves  known,  and  to 
answer  signals  from  the  ground. 

Aeroplanes  on  contact  patrol  must  not  be  called  upon  to  report 
regarding  hostile  batteries,  or  to  check  the  fires  of  our  artillery,  which 
is  the  duty  of  the  machines  working  with  the  artillery.  From  the 
position  from  which  they  work  they  are,  however,  very  well  placed  to 

1  Forward  trenches  from  which  assault  is  made. 


13 


keep  our  artillery  informed  as  to  the  movements  of  the  enemy  in 
immediate  contact  with  our  infantry;  they  should  watch  especially 
for  movements  of  immediate  reserves,  massing  of  troops  for  counter 
attack,  machine  guns,  and  strong  points  holding  up  our  advance,  and 
targets  of  such  nature,  and  send  the  information  to  the  artillery  by 
wireless,  using  the  zone  call '  system  as  used  by  the  artillery  ma- 
chines. 


24 


23 


22 


21 


20 


30 


31 


33 


34 


i  The  map  of  area  is  divided  into  zones  of  1  kilometer  square,  and  the  position  of 
targets  designated  by  their  coordinates;  thus,  a  target  at  "X"  is  reported  215-315. 


o 


LIBRARY  FACILITY 


A     000550154     9 


